Electrons

[StringJunky]

Are electrons considered to be in a superposition of locations within its orbital when not being observed i.e. smeared out in the field in effect? When you measure it, the field becomes excited in a single location?

[swansont]

Superposition implies that it's in multiple allowed eigenstates, each with some amplitude which then corresponds to the probability of finding the particle in that state. If you've specifically rigged a system to have position eigenstates, then it could be in a position superposition. Otherwise, no.

[StringJunky]

Superposition implies that it's in multiple allowed eigenstates, each with some amplitude which then corresponds to the probability of finding the particle in that state. If you've specifically rigged a system to have position eigenstates, then it could be in a position superposition. Otherwise, no.

I meant physically located all over, in effect, rather than in some unknown discrete location. How should I visualise it according to current thinking? When the electron is unperturbed.

Edited April 21, 2016 by StringJunky

[swansont]

I meant physically located all over, in effect, rather than in some unknown discrete location. How should I visualise it according to current thinking? When the electron is unperturbed.

 

 

In an atom? It's everywhere in the orbital.

[StringJunky]

 

 

In an atom? It's everywhere in the orbital.

OK.Thanks. That's what I wanted to know.

Edited April 21, 2016 by StringJunky

[Enthalpy]

...When you measure it, the field becomes excited in a single location?

 

If your measure tries to determine a location, then you can use a measuring particle whose position is better known than an atom's diameter and observe how frequently it interacts with the electron. Then you tell "the electron was there with that much probability". And after a successful interaction, you know that the electron has started its new life from a smaller volume.

 

But you can want to measure the momentum instead, and then the measure and the interaction would not tell where the electron is. One reason is that the measuring particle, with its well known momentum, has a badly known position.

 

So "measure" does not imply a position better known afterwards, and even less a point position.

 

If an interaction did occur, we know that the particles' attributes have concentrated within the volume range, or the momentum range, or the energy range... that is compatible to both the measured and the measuring particles. Some attributes can't be split, that's an excellent reason to keep the idea of particle. A point is not necessary for interactions, and for that purpose it can be dropped.

 

In fact, interactions are computed over both particles' volumes, like Laplacian[Psi(r₁, r₂, t etc)] and q₁q₂/(4pi*eps*|r₁-r₂|) for an electrostatic interaction, leading to a density Psi of the particle pair as a function of r₁, r₂, t etc - except that it's pretty much unsolvable by hand.

 

Or in a quantum well or a superlattice, the electron that absorbs or emits a photon is delocalized over many atoms before, during and after the event, and the photon interacts over that size.

 

QM courses use to begin with the double slit experiment, alas, which is misleading. I feel important to meditate instead the orbitals observed by an atomic force microscope

http://www.zurich.ibm.com/st/atomic_manipulation/pentacene.html (search AFM pentacene)

It's all the time the same electron pair at the CO molecule that senses the same electron pair making the Highest Occupied Molecular Orbital at pentacene.

[StringJunky]

 

If your measure tries to determine a location, then you can use a measuring particle whose position is better known than an atom's diameter and observe how frequently it interacts with the electron. Then you tell "the electron was there with that much probability". And after a successful interaction, you know that the electron has started its new life from a smaller volume.

 

But you can want to measure the momentum instead, and then the measure and the interaction would not tell where the electron is. One reason is that the measuring particle, with its well known momentum, has a badly known position.

 

So "measure" does not imply a position better known afterwards, and even less a point position.

 

If an interaction did occur, we know that the particles' attributes have concentrated within the volume range, or the momentum range, or the energy range... that is compatible to both the measured and the measuring particles. Some attributes can't be split, that's an excellent reason to keep the idea of particle. A point is not necessary for interactions, and for that purpose it can be dropped.

 

In fact, interactions are computed over both particles' volumes, like Laplacian[Psi(r₁, r₂, t etc)] and q₁q₂/(4pi*eps*|r₁-r₂|) for an electrostatic interaction, leading to a density Psi of the particle pair as a function of r₁, r₂, t etc - except that it's pretty much unsolvable by hand.

 

Or in a quantum well or a superlattice, the electron that absorbs or emits a photon is delocalized over many atoms before, during and after the event, and the photon interacts over that size.

 

QM courses use to begin with the double slit experiment, alas, which is misleading. I feel important to meditate instead the orbitals observed by an atomic force microscope

http://www.zurich.ibm.com/st/atomic_manipulation/pentacene.html (search AFM pentacene)

It's all the time the same electron pair at the CO molecule that senses the same electron pair making the Highest Occupied Molecular Orbital at pentacene.

Thank you for that Enthalpy.